Mini Turbo

Has anyone out there tried to put a micro computer fan on their intake, on a 2 stroke happytime? I think that if it was connected to the engines powersupply, via "the white wire" the fan speed would fluxuate with the engine speed as it generates electricity through the magneto.

reply to this thread and share any experiences with this sort of thing..:grin:

Its an interesting idea although most processor fans run at either 3.3v or 5v so you'd either have to drop the voltage or use a fan rated at 12v - I am this point assuming the chengines electrics are 12v. 6 volt wouldnt be a problem

The question would be I guess whether the output of the fan would make any real difference - and having worked in computers I think it would make a small one, the issue being whether the adjustability on the carb is fine enough to set reasonable mixture with the additional intake pressure.

I think to be honest the best thing is to try it and see... I would however suggest that you somehow (if possible) mount the fan on the inboard side of the carb so it acts like the old type rootes blower as fitted to the bentley 4 1/2 and 8 1/2 cars. This way it helps mix the fuel air as well as pressurising the induction charge - you might want to run the carb one click richer if needed

The major issue is whether it would have enough output to lower the inherant charge loss when the ports open - if it can do that then you should have some noticable performance changes...

Try it but your wasting your money, you never will be able to blow enough air with a pc fan to make a boost condition, you will probably only restrict air flow.
The atmosphere is around 1 BAR or 14.696 PSI, its a physics thing, the internal combustion engine doesn't suck air in, a low pressure area in the venturi causes atmospheric pressure to be forced in to the engine. (about as simple as i can make it )
To make a boost condition you need to blow more than 14.7 PSI, anything over (eg. 15.7 PSI) is 1 PSI of boosted air flow.

There is a lot of people trying to sell plans for an electric supercharger (essentially the computer fan idea but on a bigger scale). It would have more of a ram air effect than a boost effect as the pressure wouldnt be that much. Its definetely worth a try though. I've got a few fans laying around.

I'm sure this is a stupid question, and I feel dumb asking it, but how can you run anything on the white wire? Wouldnt you need two?? Positive and negative? Or am i missing some incredibly obvious lol

You would just earth to the motor, I have seen the electic stuff, do a search and you will find plenty of tests that prove it doesn't work.
You would gain more from a ram tube, even pointing the carb forward will have no affect because you will never go fast enough.
Have a look at big super sports bikes, they have large plenum air boxes (2 - 3 - 4 litres) with ram air, they only get a small power increase at high speed (over 100mph)

I have to agree with Phil, while you should be able to get the fan spinning by running it off the engine, you won't be able to generate enough pressure to increase performance, especially running a computer fan at the 6v or so you'll get off the magneto.

Fans are good for moving air about, and can achieve good flow rates if used correctly, but they are not good at providing any soft of significant pressure levels - blowers (superchargers and the like) which are designed to provide high positive pressures operate using impellers rotating very fast with extremely small tolerances.

Unfortunately I don't think it's an idea that's worth the trouble it'd be - think of all the air/fuel issues you'd have! :lol:

It won't work, there's more to it than just bolting a fan to the inlet side of the engine. Even if the fan does increase the pressure in the intake manifold, let's be optimistic and say 0.5Bar (normally pressure turbo's boost) on top of atmospheric pressure, the extra air and fuel mixture will "fall" out the exhaust port because the port timing (overlap) differs alot between normal aspirated engines and boosted engines......
Secondly the engine is not designed to absorbed the extra stresses and forces resulting from the increased performance (if it really happened) and therefore will either pull head studs or break the piston or even destroy the engine casings.

Not to be one to dampen creativity but whatever fan you pick will likely be no more effective than blowing into the carb as hard as you can.

Spooling a turbo is not anything like swirling a bit of air in front of the carb. In fact I would bet that you would see a decrease in performace. I bored my carb by about 2mm and saw a bit more throttle response (opened my exhaust up too). I'd guess that the fan running or not would actually impeed air flow (not to mention the current draw)

On a 2 stroke even if you had a real turbo and got it to spool you would now have something forcing the fuel/air mix out the exhaust before it was ignited. To compensate for this you would have to have an exhaust that would make a ton of back pressure. Kinda back to square one then.

But give it a try. Do it the simple way. Take off your air cleaner, swipe your wifes hair dryer and let her rip............

There is a lot of people trying to sell plans for an electric supercharger (essentially the computer fan idea but on a bigger scale). It would have more of a ram air effect than a boost effect as the pressure wouldnt be that much. Its definetely worth a try though. I've got a few fans laying around.

I'm sure this is a stupid question, and I feel dumb asking it, but how can you run anything on the white wire? Wouldnt you need two?? Positive and negative? Or am i missing some incredibly obvious lol

Click to expand...

The frame acts as ground.
As for using the magneto to run the fan, magneto voltage does not vary with engine speed in a linear fashion, infact it hardly changes at all. Or else your lights would be dim at idle, and blowing bulbs near redline. the magneto is designed to saturate at a certain RPM.

As for the idea itself, it is feasible but impractical or everyday use. Personally I would just stick to improving breathing.

I dont like to blow my own horn,, but i am an ASE certified auto tech. I have seen poeple selling and installing every thing from modified vacumes to devices in the air stream in an effort to "Boost" power. the only ones I have seen actuley work so far have been traditional turbos, super charchers(IE blowers) and nitrus. and none of the electric "turbos" I have seen have done anny thing but put a drag on the charging system.
Sorry to burs your bubble guys and gals.

Turbo's -& superchargers are all about 'volumetric efficiency' - increasing the ammount of fuel/air you can cram into your cylinder, thus producing more power. The truth is that a decent expansion chamber carefully set up will be much more effective at doing that.
Keep tinkering & thinking though, it's great.
I supercharged a 49cc honda monkey bike some years ago. I took the inards from a pneaumatic rotary sander (as used in crash repair shops). Enlarged the inlet & outlet holes,pressed it all into a block of aluminium & drove it with a tiny 8mm v belt & a washing machine pulley with a groove machined in the flywheel.About 2.6 :1. I had 2 flats machined on the aluminium casing & mounted the inlet & outlet manifolds on it.I used a 19mm delorto flatslide from a fantic super rocket.. It sounded like a dentist drill! but it was never properly sorted,the manifold was too long & the blower bearings were sealed-yet ran at 18,000rpm!
Then years later I sent a honda 70cc camshaft off to Ivan Tigh Camshafts here in Australia. I asked him for the most wild grind he could manage without making it too difficult to start or idle. It was a winner. In those days it cost $80. The power gain was unbelievable!...waaaay better than my half baked blower.
The point of all this is that usually a simple & cheaper mod can give you the extra power you want.
cheers
Simon

This idea of using a teensy computer fan to as a blower to get the engine to ingest more air is utter nonsense,even if the white wire would be able to run the thing.the efect would be infinitesimal,even a small engine sucks in lots of air (I'll spare you the calculation),far far more than such fan could ever provide.If fact the intake air would prob. drive the fan.instad of the converse.